Stimulant Arousal/Reward vs Attention Networks (Kay 2025)
1 Kay et al. 2025 — Stimulant Medications Affect Arousal and Reward, Not Attention Networks
Full Citation:: Kay BP, Wheelock MD, Siegel JS, et al. Stimulant medications affect arousal and reward, not attention networks. Cell. 2025;188(26):7529–7546.e20. (Kay et al. 2025) DOI:: 10.1016/j.cell.2025.11.039 PMID:: 41448140 Study Design:: Large-sample resting-state fMRI (ABCD Study, n=11,875; n=337 taking stimulants on scan day) validated by a precision imaging drug trial (n=5 healthy adults, methylphenidate 40 mg, 165–210 min scan per participant) Key Findings::
- Stimulant-related functional-connectivity (FC) differences were largest in somato-cognitive action/motor (arousal) and salience/parietal-memory (reward) networks, but were NOT significant in dorsal or ventral attention or frontoparietal control networks, despite 95% power to detect previously reported attention-network effect sizes (d≈0.89).
- Stimulant FC patterns resembled those of longer sleep (arousal) and correlated with norepinephrine-transporter density maps; stimulants reversed the FC and cognitive effects of short sleep.
- Stimulants improved cognitive performance only in children with ADHD or sleep deprivation, not in healthy well-rested children; children with ADHD improved to the level of the rest of the cohort without increasing cognitive ability.
- The authors conclude stimulants increase vigilance and perceived task value (drive/effort/persistence) rather than attention-network capacity.Conclusion: The strongest human evidence to date that therapeutic stimulants act on arousal and reward salience, not attention systems. Reframes a positive stimulant response as a marker of low arousal/reward salience, not augmented attentional capacity. Limitations: General-population/ADHD children plus 5 healthy adults; no ME/CFS cohort; methylphenidate validation arm n=5; cross-sectional ABCD data cannot establish causality; imprecise “attention” construct and heterogeneous prior network definitions limit comparison. Certainty Assessment: 0.80 raw × 0.75 (general population/ADHD) = discounted 0.60 (neuroscience dissociation)
2 Ilieva et al. 2015 — Meta-analysis of Prescription Stimulant Effects on Healthy Cognition
Full Citation:: Ilieva IP, Hook CJ, Farah MJ. Prescription stimulants’ effects on healthy inhibitory control, working memory, and episodic memory: a meta-analysis. Journal of Cognitive Neuroscience. 2015;27(6):1069–1089. (I. P. Ilieva, Hook, and Farah 2015) DOI:: 10.1162/jocn_a_00776 PMID:: 25591060 Study Design:: Meta-analysis (48 studies; n=1,409 healthy participants) Key Findings::
- Only small significant enhancement of inhibitory control and short-term episodic memory; working-memory effect small and dependent on analytic approach.
- Long-term and working-memory effects were qualified by publication bias; delayed episodic memory effect was medium but not robust.
- Authors conclude the effect of amphetamine and methylphenidate on healthy cognition is probably modest overall, and users may use stimulants more for energy/motivation than cognition.Conclusion: Direct meta-analytic counter-evidence to attention/cognitive-capacity enhancement in healthy people, converging on the motivation/energy interpretation later formalized by Kay 2025. Limitations: Healthy participants only; heterogeneous tasks and doses; publication-bias concern within the included literature. Certainty Assessment: 0.75 raw × 0.75 (general population) = discounted 0.56 (meta-analysis null)
3 Ilieva et al. 2013 — Objective vs Subjective Amphetamine Effects in Healthy People
Full Citation:: Ilieva I, Boland J, Farah MJ. Objective and subjective cognitive enhancing effects of mixed amphetamine salts in healthy people. Neuropharmacology. 2013;64:496–505. (I. Ilieva, Boland, and Farah 2013) DOI:: 10.1016/j.neuropharm.2012.07.021 PMID:: 22884611 Study Design:: Double-blind, crossover, placebo-controlled trial in healthy young adults (13 cognitive measures) Key Findings::
- No enhancement of any cognitive ability by mixed amphetamine salts in general; only a minority of tasks showed moderation by baseline ability and COMT genotype.
- Despite the objective null, participants reported an illusory perception of cognitive enhancement.Conclusion: A clean human demonstration that stimulants can improve perceived performance without improving objective cognitive ability — the subjective/objective dissociation central to the stimulant-response reframing. Limitations: Modest n; healthy young adults; single dose of one amphetamine formulation. Certainty Assessment: 0.70 raw × 0.75 (general population) = discounted 0.53 (subjective-objective dissociation)
4 Roberts et al. 2020 — Meta-analyses of Cognitive Enhancement in Healthy Adults
Full Citation:: Roberts CA, Jones A, Sumnall H, Gage SH, Montgomery C. How effective are pharmaceuticals for cognitive enhancement in healthy adults? A series of meta-analyses of cognitive performance during acute administration of modafinil, methylphenidate and D-amphetamine. European Neuropsychopharmacology. 2020;38:40–62. (Roberts et al. 2020) DOI:: 10.1016/j.euroneuro.2020.07.002 PMID:: 32709551 Study Design:: PRISMA series of meta-analyses (k=47 studies) in healthy non-sleep-deprived adults Key Findings::
- Across executive function, working memory, recall, and selective/sustained attention, evidence of cognitive enhancement was limited and inconsistent in rested healthy adults.
- Benefits appeared mainly in sleep-deprived or lower-baseline conditions rather than as broad capacity gains.Conclusion: Converging meta-analytic evidence that stimulants do not raise attention/cognition capacity in rested healthy people, reinforcing the arousal/deficit-rescue interpretation. Limitations: Healthy adults only; heterogeneity of doses, tasks, and designs. Certainty Assessment: 0.75 raw × 0.75 (general population) = discounted 0.56 (meta-analysis)
5 Repantis et al. 2010 — Systematic Review of Modafinil/MPH Neuroenhancement
Full Citation:: Repantis D, Schlattmann P, Laisney O, Heuser I. Modafinil and methylphenidate for neuroenhancement in healthy individuals: a systematic review. Pharmacological Research. 2010;62(3):187–206. (Repantis et al. 2010) DOI:: 10.1016/j.phrs.2010.04.002 PMID:: 20416377 Study Design:: Systematic review Key Findings::
- Cognitive effects of modafinil and methylphenidate in healthy individuals were inconsistent and limited to specific subgroups or task conditions.
- Mood, arousal, and wakefulness effects were more consistent than cognitive-enhancement effects.Conclusion: An early systematic expression of the arousal/mood-vs-cognition dissociation later demonstrated by Kay 2025. Limitations: Older review; pre-modern meta-analytic methods; healthy populations only. Certainty Assessment: 0.65 raw × 0.75 (general population) = discounted 0.49 (systematic review)
6 Marraccini et al. 2016 — Meta-analysis of Prescription Stimulant Neurocognitive Effects
Full Citation:: Marraccini ME, Weyandt LL, Rossi JS, Gudmundsdottir BG. Neurocognitive enhancement or impairment? A systematic meta-analysis of prescription stimulant effects on processing speed, decision-making, planning, and cognitive perseveration. Experimental and Clinical Psychopharmacology. 2016;24(4):269–284. (Marraccini et al. 2016) DOI:: 10.1037/pha0000079 PMID:: 27454675 Study Design:: Systematic meta-analysis Key Findings::
- Prescription stimulant effects on processing speed, decision-making, planning, and perseveration were small and domain-specific.
- Evidence included both enhancement and impairment depending on task and population.Conclusion: Supports the view that stimulants do not uniformly improve higher cognition — a further null-leaning anchor against a general attention-capacity gain. Limitations: Heterogeneous outcome measures; mixed populations. Certainty Assessment: 0.60 raw × 0.75 (general population) = discounted 0.45 (meta-analysis)
7 Chong et al. 2023 — Amphetamines Improve Motivation to Invest Effort in ADHD
Full Citation:: Chong TT-J, Fortunato E, Bellgrove MA. Amphetamines improve the motivation to invest effort in attention-deficit/hyperactivity disorder. Journal of Neuroscience. 2023;43(41):6898–6908. (Chong, Fortunato, and Bellgrove 2023) DOI:: 10.1523/JNEUROSCI.0982-23.2023 PMID:: 37666665 Study Design:: Within-subject effort-based decision task (20 adults with ADHD on amphetamine medication; 24 controls) Key Findings::
- Amphetamines increased willingness to invest effort for reward rather than improving task ability — reward-effort invigoration.
- Effort sensitivity was altered in ADHD and partially normalized by medication.Conclusion: Human evidence that stimulant benefit is motivational/effort-based, aligning with Kay 2025’s reward-salience account and refining the ME/CFS “drive, not capacity” inference. Limitations: ADHD population (not ME/CFS); modest n; amphetamine class only. Certainty Assessment: 0.70 raw × 0.75 (general/ADHD population) = discounted 0.53 (effort invigoration)
8 Bowman et al. 2023 — Smart Drugs Increase Level but Decrease Quality of Effort
Full Citation:: Bowman E, Coghill D, Murawski C, Bossaerts P. Not so smart? “Smart” drugs increase the level but decrease the quality of cognitive effort. Science Advances. 2023;9(28):eadd4165. (Bowman et al. 2023) DOI:: 10.1126/sciadv.add4165 PMID:: 37315143 Study Design:: Placebo-controlled study in healthy adults (knapsack optimization task) Key Findings::
- Methylphenidate, dextroamphetamine, and modafinil significantly decreased attained task value (quality of effort) and increased decision time/steps (level of effort).
- Solution strategies became more random and individual productivity differences reversed.Conclusion: Dissociates effort/motivation increase from cognitive output — stimulants can raise drive while degrading the quality of cognitive work, an important nuance for the masking/overexertion hazard. Limitations: Healthy adults; single stylized task; does not model chronic illness. Certainty Assessment: 0.70 raw × 0.75 (general population) = discounted 0.53 (effort-quality dissociation)
9 Greenhouse-Tucknott et al. 2025 — Perceived Fatigue, Effort, and Confidence
Full Citation:: Greenhouse-Tucknott A, Wrightson JG, Berens S, Dekerle J, Harrison NA. Perceived fatigue does not alter effort-based decision making but does undermine confidence in the ability to perform physical actions. Physiology & Behavior. 2025;291:114792. (Greenhouse-Tucknott et al. 2025) DOI:: 10.1016/j.physbeh.2024.114792 PMID:: 39730065 Study Design:: Within-subject rewarded effort-based decision task (22 healthy males) Key Findings::
- Perceived fatigue did not shift the cost-benefit valuation of effort.
- Fatigue reduced confidence in the ability to perform physical actions.Conclusion: Suggests fatigue acts on self-efficacy/arousal rather than reward-effort valuation per se — a boundary condition for the arousal/reward model and a caution against over-generalizing reward explanations to fatigue. Limitations: Healthy males; physical-effort task; not ME/CFS. Certainty Assessment: 0.60 raw × 0.75 (general population) = discounted 0.45 (effort/confidence boundary)
10 Rubia et al. 2014 — Competing Account: Stimulants Modulate Cognitive-Control Regions
Full Citation:: Rubia K, Alegria AA, Cubillo AI, Smith AB, Brammer MJ, Radua J. Effects of stimulants on brain function in attention-deficit/hyperactivity disorder: a systematic review and meta-analysis. Biological Psychiatry. 2014;76(8):616–628. (Rubia et al. 2014) DOI:: 10.1016/j.biopsych.2013.10.016 PMID:: 24314347 Study Design:: Systematic review and meta-analysis of task-based fMRI studies of stimulant effects in ADHD Key Findings::
- Stimulants most consistently increased right inferior frontal cortex/insula activation, interpreted as an effect on cognitive-control regions.
- Authors propose these neurocognitive effects may underlie positive clinical effects.Conclusion: The leading competing account to Kay 2025 — stimulants acting on cognitive-control/attention-related regions. Kay 2025 attributes the discrepancy largely to smaller ROI-based designs and notes prior attention-network effect sizes were within their detectable range. Retained as the competing-mechanism counterweight. Limitations: Task-fMRI sensitive to performance confounds; older, smaller studies; ADHD population. Certainty Assessment: 0.65 raw × 0.75 (general/ADHD population) = discounted 0.49 (competing mechanism)
11 Oliva et al. 2025 — Safety of Stimulants Across Patient Populations
Full Citation:: Oliva HNP, Prudente TP, Mayerson TF, et al. Safety of stimulants across patient populations: a meta-analysis. JAMA Network Open. 2025;8(5):e259492. (Oliva et al. 2025) DOI:: 10.1001/jamanetworkopen.2025.9492 PMID:: 40343695 Study Design:: Meta-analysis of stimulant safety across patient populations (beyond ADHD, including off-label use) Key Findings::
- Quantifies the cardiovascular, psychiatric, sleep, and appetite-related adverse-event profile of stimulant medications.
- Establishes the safety ceiling relevant to off-label stimulant use in conditions with fatigue/cognitive complaints.Conclusion: Provides the harm counterweight for the ME/CFS stimulant differential: as stimulants raise arousal and drive without restoring energy supply, their cardiovascular/psychiatric/sleep risks are the relevant safety constraint. Limitations: Heterogeneous populations; off-label ME/CFS use not separately studied. Certainty Assessment: 0.75 raw × 0.75 (general population) = discounted 0.56 (safety meta-analysis)
12 Nourredine et al. 2026 — ADHD Pharmacological Interventions Network Meta-analysis
Full Citation:: Nourredine M, Jurek L, Hamza T, et al. Pharmacological interventions for attention-deficit/hyperactivity disorder: a systematic review and dose-effect network meta-analysis. Lancet Psychiatry. 2026;13(6):485–495. (Nourredine et al. 2026) DOI:: 10.1016/S2215-0366(26)00091-X PMID:: 42134365 Study Design:: Systematic review and dose-effect network meta-analysis Key Findings::
- Ranks pharmacological interventions for ADHD by efficacy and tolerability, with dose-response structure for stimulants and non-stimulants.
- Provides modern comparative estimates for the stimulant class.Conclusion: The largest modern synthesis of stimulant dose-response/tolerability; useful for dose-window and safety-ladder reasoning in the ME/CFS stimulant differential. ADHD population, not ME/CFS. Limitations: ADHD population only; does not address ME/CFS or chronic fatigue. Certainty Assessment: 0.80 raw × 0.75 (general/ADHD population) = discounted 0.60 (network meta-analysis)
13 Ahmed et al. 2010 — Lactate Activates GPR81 to Inhibit Lipolysis
Full Citation:: Ahmed K, Tunaru S, Tang C, Müller M, Gille A, Sassmann A, Hanson J, Offermanns S. An autocrine lactate loop mediates insulin-dependent inhibition of lipolysis through GPR81. Cell Metabolism. 2010;11(4):311–319. (Ahmed et al. 2010) DOI:: 10.1016/j.cmet.2010.02.012 PMID:: 20374963 Study Design:: Mouse GPR81-knockout and isolated-adipocyte mechanistic study Key Findings::
- Lactate activates the Gi-coupled receptor GPR81 (HCAR1) on adipocytes, inhibiting adenylyl cyclase.
- Insulin's antilipolytic effect is strongly reduced in GPR81-deficient mice, via a lactate autocrine/paracrine loop.
- Establishes lactate as a bona-fide cell-surface GPCR ligand, not inert metabolic waste.Conclusion: Foundational demonstration that lactate signals through GPR81/HCAR1 with systemic metabolic function — the receptor axis underlying the lactate-as-signal hypothesis. Limitations: Mouse and isolated adipocytes; adipose-restricted; does not test immune or brain GPR81. Certainty Assessment: 0.70 raw × 0.50 (animal) = discounted 0.35
14 Pucino et al. 2019 — Lactate Rewires CD4+ T Cells in Chronic Inflammation
Full Citation:: Pucino V, Certo M, Bulusu V, et al. Lactate buildup at the site of chronic inflammation promotes disease by inducing CD4+ T cell metabolic rewiring. Cell Metabolism. 2019;30(6):1055–1074.e8. (Pucino et al. 2019) DOI:: 10.1016/j.cmet.2019.10.004 PMID:: 31708446 Study Design:: Human CD4+ T cells + mouse models + rheumatoid-arthritis patient tissue Key Findings::
- Lactate accumulated in inflamed synovium is taken up by CD4+ T cells and drives a pro-inflammatory IL-17-producing program via metabolic reprogramming (SLC5A12/MCT upregulation).
- Blocking lactate transport/uptake suppresses this inflammatory phenotype.Conclusion: Lactate is a direct driver of T-cell effector programs in chronic inflammatory disease — the immune-metabolic reprogramming axis that links lactate to ME/CFS-relevant immune dysfunction. Limitations: RA patients + mouse; CD4 subset only; ME/CFS not tested. Certainty Assessment: 0.75 raw × 0.50 (animal/human-cell mechanism) = discounted 0.38
15 Morland et al. 2017 — Exercise Signals the Brain via Lactate Receptor HCAR1
Full Citation:: Morland C, Andersson KA, Haugen ØP, et al. Exercise induces cerebral VEGF and angiogenesis via the lactate receptor HCAR1. Nature Communications. 2017;8:15557. (Morland et al. 2017) DOI:: 10.1038/ncomms15557 PMID:: 28534495 Study Design:: HCAR1-knockout mouse; exercise and lactate-injection paradigms Key Findings::
- HCAR1 is enriched on pial fibroblast-like and pericyte-like cells lining cerebral vessels.
- Lactate (from exercise or injection) raises brain VEGFA and capillary density in wild-type but not HCAR1-knockout mice.Conclusion: Lactate is a concrete muscle-to-brain inter-organ signal coupling exertion to cerebrovascular adaptation — directly relevant to the exercise/PEM-vs-brain-perfusion axis. Limitations: Mouse; no fatigue/behavioral readout; HCAR1-specific. Certainty Assessment: 0.70 raw × 0.50 (animal) = discounted 0.35
16 Hoque et al. 2014 — Lactate Suppresses Innate Immunity via GPR81
Full Citation:: Hoque R, Farooq A, Ghani A, Gorelick F, Mehal WZ. Lactate reduces liver and pancreatic injury in Toll-like receptor- and inflammasome-mediated inflammation via GPR81-mediated suppression of innate immunity. Gastroenterology. 2014;146(7):1763–1774. (Hoque et al. 2014) DOI:: 10.1053/j.gastro.2014.03.014 PMID:: 24657625 Study Design:: Mouse TLR/inflammasome organ-injury model Key Findings::
- Lactate, via GPR81, suppresses TLR/NLRP3 inflammasome signal-1 in innate immune cells and reduces organ injury.Conclusion: Defines the protective anti-inflammatory arm of lactate signaling, counterbalancing the pro-inflammatory T-cell axis — the dual GPR81 effector network posited as dysfunctional in ME/CFS. Limitations: Mouse; liver/pancreas injury model, not chronic fatigue. Certainty Assessment: 0.70 raw × 0.50 (animal) = discounted 0.35
17 Colegio et al. 2014 — Lactic Acid Polarizes Macrophages
Full Citation:: Colegio OR, Chu NQ, Szabo AL, et al. Functional polarization of tumour-associated macrophages by tumour-derived lactic acid. Nature. 2014;513(7519):559–563. (Colegio et al. 2014) DOI:: 10.1038/nature13490 PMID:: 25043024 Study Design:: Mouse tumour model and macrophage polarization assays Key Findings::
- Tumour-derived lactic acid induces an M2-like macrophage program (VEGF, arginase 1) independent of hypoxia.Conclusion: Canonical evidence that lactate is a direct immunomodulatory signal rather than a passive metabolite — supplying the macrophage-polarization arm relevant to ME/CFS neuroinflammation. Limitations: Tumour model; mouse/cell; not ME/CFS. Certainty Assessment: 0.75 raw × 0.50 (animal) = discounted 0.38
18 Yang et al. 2014 — Lactate Potentiates NMDA Signaling and Plasticity
Full Citation:: Yang J, Ruchti E, Petit JM, Jourdain P, Grenningloh G, Allaman I, Magistretti PJ. Lactate promotes plasticity gene expression by potentiating NMDA signaling in neurons. Proceedings of the National Academy of Sciences. 2014;111(33):12228–12233. (Yang et al. 2014) DOI:: 10.1073/pnas.1322912111 PMID:: 25071212 Study Design:: Primary neuronal culture + in vivo mouse cortex Key Findings::
- Lactate potentiates NMDA-receptor currents and Erk1/2 signaling, and raises neuronal NADH (redox), inducing plasticity genes (Arc, c-Fos, Zif268).
- NADH alone mimics lactate's NMDA effects, pointing to redox as the mediator.Conclusion: Extends lactate’s CNS role beyond fuel into activity-dependent plasticity/redox signaling — the molecular substrate for a signaling (not merely energetic) astrocyte–neuron lactate shuttle. Limitations: In vitro primary neurons + mouse cortex; no fatigue/behavioral readout. Certainty Assessment: 0.65 raw × 0.40 (in vitro) = discounted 0.26
19 Halestrap & Wilson 2012 — The Monocarboxylate Transporter Family
Full Citation:: Halestrap AP, Wilson MC. The monocarboxylate transporter family—role and regulation. IUBMB Life. 2012;64(2):109–119. (Halestrap and Wilson 2012) DOI:: 10.1002/iub.572 PMID:: 22162139 Study Design:: Authoritative review of MCT1–4 (SLC16A1/3/7/8) transporter biology Key Findings::
- MCT1–4 catalyze proton-linked lactate transport with tissue-specific expression; roles in brain, muscle, heart, and T-cell activation.Conclusion: Lactate’s signaling reach is gated by MCT expression — so transporter (not only GPR81) expression is a candidate dysregulation node in ME/CFS. Limitations: Review; general biology, not ME/CFS. Certainty Assessment: 0.60 raw × 0.75 (general biology) = discounted 0.45
20 Haunhorst et al. 2025 — PEM as Microvascular + Immunometabolic
Full Citation:: Haunhorst S, Dudziak D, Scheibenbogen C, et al. Towards an understanding of physical activity-induced post-exertional malaise: insights into microvascular alterations and immunometabolic interactions in post-COVID condition and ME/CFS. Infection. 2025;53(1):1–13. (Haunhorst et al. 2025) DOI:: 10.1007/s15010-024-02386-8 PMID:: 39240417 Study Design:: Narrative review spanning post-COVID condition and ME/CFS Key Findings::
- Frames PEM as microvascular alterations plus immunometabolic interactions.
- Positions glycolytic/lactate-immunometabolic reprogramming as a candidate PEM mechanism rather than mere lactate accumulation.Conclusion: The ME/CFS-facing conceptual bridge for the lactate-signaling angle, and a competing account to the pure deconditioning explanation. Limitations: Review, no new primary data; PEM pathomechanisms remain poorly elucidated. Certainty Assessment: 0.55 raw × 0.85 (post-viral/ME/CFS review) = discounted 0.47
21 Stacpoole et al. 2006 — DCA for Congenital Lactic Acidosis (RCT)
Full Citation:: Stacpoole PW, Kerr DS, Barnes C, et al. Controlled clinical trial of dichloroacetate for treatment of congenital lactic acidosis in children. Pediatrics. 2006;117(5):1519–1531. (Stacpoole et al. 2006) DOI:: 10.1542/peds.2005-1226 PMID:: 16651305 Study Design:: Double-blind randomized controlled trial (n=43 children) Key Findings::
- Oral DCA (a PDK inhibitor activating pyruvate dehydrogenase) reduced blood lactate and gave transient neurologic improvement.
- Dose-limiting peripheral neuropathy was the main toxicity.Conclusion: The only RCT-grade evidence for the “inhibit PDK → lower lactate” strategy; its neuropathy toxicity is the safety ceiling for any ME/CFS use. Limitations: Different disease (congenital lactic acidosis, not ME/CFS); small n; neuropathy toxicity. Certainty Assessment: 0.70 raw × 0.75 (different disease population) = discounted 0.53
22 Teitelbaum et al. 2006 — D-Ribose in CFS/Fibromyalgia (Pilot)
Full Citation:: Teitelbaum JE, Johnson C, St Cyr J. The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study. Journal of Alternative and Complementary Medicine. 2006;12(9):857–862. (Teitelbaum, Johnson, and St Cyr 2006) DOI:: 10.1089/acm.2006.12.857 PMID:: 17109576 Study Design:: Open-label uncontrolled pilot (n=41 CFS/FMS patients) Key Findings::
- ~66% reported subjective improvement in energy, sleep, mental clarity and well-being with D-ribose 5g t.i.d.Conclusion: Weak human signal for “energy-substrate support → relieve glycolytic strain”; hypothesis only, not a recommendation. Limitations: Open-label; no placebo/blinding; mixed CFS+FM; subjective endpoints; low-tier journal. Certainty Assessment: 0.40 raw × 0.80 (FM/comorbid) = discounted 0.32
23 Kuratsune et al. 1998 — Serum Acylcarnitine Deficiency in ME/CFS
Full Citation:: Kuratsune H, Yamaguti K, Lindh G, et al. Low levels of serum acylcarnitine in chronic fatigue syndrome and chronic hepatitis type C, but not seen in other diseases. International Journal of Molecular Medicine. 1998;2(1):51–56. (Kuratsune et al. 1998) DOI:: 10.3892/ijmm.2.1.51 PMID:: 9854142 Study Design:: Cross-national observational biomarker study (Swedish n=57 + Japanese cohorts) Key Findings::
- Serum acylcarnitine deficiency present in ME/CFS patients in two independent populations, but not in most other diseases.
- Implies impaired carnitine/fatty-acid energy metabolism and a compensatory glycolytic/lactate shift.Conclusion: Foundational, cross-nationally replicated biomarker rationale for carnitine/acetyl-L-carnitine as a lactate-lowering (energy-rerouting) intervention in ME/CFS. Limitations: Observational; single lab; 1998; no intervention arm. Certainty Assessment: 0.50 raw × 1.00 (ME/CFS) = discounted 0.50
24 Forsythe & Schmidt 2000 — Sodium Bicarbonate for Lactic Acidosis
Full Citation:: Forsythe SM, Schmidt GA. Sodium bicarbonate for the treatment of lactic acidosis. Chest. 2000;117(1):260–267. (Forsythe and Schmidt 2000) DOI:: 10.1378/chest.117.1.260 PMID:: 10631227 Study Design:: Critical literature review (competing/harm arm) Key Findings::
- The rationale for IV sodium bicarbonate in lactic acidosis is not supported: it does not raise intracellular pH, may worsen hemodynamics, and lacks benefit evidence.Conclusion: Establishes the null/harm boundary for the “buffer the lactate” intervention family — buffering lactate itself has no demonstrated efficacy and potential harm in ME/CFS. Limitations: Critical-care context, not ME/CFS; review. Certainty Assessment: 0.50 raw × 0.75 (general/critical-care population) = discounted 0.38
25 Bager et al. 2021 — High-Dose Thiamine for Fatigue in IBD (RCT)
Full Citation:: Bager P, Hvas CL, Rud CL, Dahlerup JF. Randomised clinical trial: high-dose oral thiamine versus placebo for chronic fatigue in patients with quiescent inflammatory bowel disease. Alimentary Pharmacology & Therapeutics. 2021;53(1):79–86. (Bager et al. 2021) DOI:: 10.1111/apt.16166 PMID:: 33210299 Study Design:: Randomized placebo-controlled trial (n=60) Key Findings::
- High-dose oral thiamine (vitamin B1, a pyruvate-dehydrogenase cofactor) significantly reduced fatigue vs placebo in quiescent IBD.Conclusion: RCT-grade, fatigue-specific human evidence for the “B1 cofactor → restore PDH → lower lactate” strategy — the closest human data to a ME/CFS thiamine trial. Limitations: IBD (not ME/CFS); moderate n; single study. Certainty Assessment: 0.65 raw × 0.75 (different disease population) = discounted 0.49